The M & M Lab:

What if we had 6.02 x 1023 M&M’s and we spread them out over the whole state of Washington, how deep would it be?

YumYum

The MoleThe Mole

1 dozen =1 gross =

1 ream =

1 mole =

12

144

500

6.02 x 1023

That is a REALLY BIG number…

Suppose we invented a new collection unit called a Wik. One Wik contains 8 objects.

1. How many paper clips in 1 Wik?

a) 1 b) 4 c) 8

2. How many oranges in 2.0 Wik?

a) 4 b) 8 c) 16

3. 40 gummy bears is how many Wiks?

a) 5 b) 10 c) 20

Learning CheckLearning Check

Just How Big is a Mole?Just How Big is a Mole?

• Enough soft drink cans to cover the surface of the earth to a depth of over 200 miles.

• If you had Avogadro's number of unpopped popcorn kernels, and spread them across the United States of America, the country would be covered in popcorn to a depth of over 9 miles.

• If we were able to count atoms at the rate of 10 million per second, it would take about 2 billion years to count the atoms in one mole.

A mole = Avogadro’s NumberA mole = Avogadro’s Number6.02 x 1023

Otherwise known as“Avogadro’s Number” in honor of the Italian chemist Amadeo Avogadro (1776-1855).

Amadeo Avogadro

The MoleThe Mole• 1 dozen cookies = 12 cookies• 1 mole of cookies = 6.02 X 1023 cookies

• 1 dozen cars = 12 cars• 1 mole of cars = 6.02 X 1023 cars

• 1 dozen Al atoms = 12 Al atoms• 1 mole of Al atoms = 6.02 X 1023 Al atoms

Note that the NUMBER is always the same, but the MASS is very different!

Mole is abbreviated mol

= 6.02 x 1023 C atoms

= 6.02 x 1023 H2O molecules

= 6.02 x 1023 NaCl

“molecules”

A Mole of ParticlesA Mole of Particles Contains 6.02 x 1023 particles

1 mole C atoms

1 mole H2O molecules

1 mole NaCl molecules

6.02 x 1023 particles

1 mole particles

or

1 mole particles

6.02 x 1023 particles

Note that a particle could be anything!

Avogadro’s Number as Avogadro’s Number as Conversion FactorConversion Factor

The MoleThe MoleSo how do we use the mole in Chemistry?

•There are 6.94 grams of lithium in one mole of Li atoms.

•If we have one mole of Carbon how many grams do we have?

•Notice, these are called atomic weights on your periodic charts

Using the MoleUsing the Mole

•We use the mole to convert a measured mass of an element to find the # of atoms that are present.

•Ex: Mass 12g of carbon-12 and you know you’ll have 1 mole of carbon which is 6.02 x 1023 atoms of carbon.(cool, eh?)

Calculations with Moles:Calculations with Moles:Converting moles to gramsConverting moles to grams

How many grams of lithium are in 3.50 moles of lithium?

3.50 mol Li= g Li

1 mol Li

6.94 g Li24.3

There are 24.3 grams of lithium in 3.50 moles of lithium.

Calculations with Moles:Calculations with Moles:Converting grams to molesConverting grams to moles

How many moles of lithium are in 18.2 grams of lithium?

18.2 g Li= mol Li

6.94 g Li

1 mol Li2.62

There are 2.62 moles of lithium in 18.2 grams of lithium.

Calculations with Moles:Calculations with Moles:Using Avogadro’s NumberUsing Avogadro’s Number

How many atoms of lithium are in 3.50 moles of lithium?

3.50 mol Li = atoms Li

1 mol Li

6.02 x 1023 atoms Li 2.11 x 1024

There are 2.11 x 1024 atoms of lithium in 3.50 moles of lithium.

Calculations with Moles:Calculations with Moles:Using Avogadro’s NumberUsing Avogadro’s Number

How many atoms of lithium are in 18.2 g of lithium?

18.2 g Li

= atoms Li

1 mol Li 6.02 x 1023 atoms Li

1.58 x 1024

6.94 g Li 1 mol Li